Treatment liquid supply system

Abstract

In a treatment liquid supply system that supplies treatment liquid used for coating industrial objects for film formation including a semiconductor substrate, a display substrate, a glass and the like, a nozzle connected to a treatment liquid tank vacuum-sucks and injects the treatment liquid from the treatment liquid tank due to a negative pressure occurring in the nozzle, wherein supply control of a small flow amount of the treatment liquid to the nozzle can be performed due to a difference pressure between pressure in the treatment liquid tank and the negative pressure occurring in the nozzle.

1. A treatment liquid supply system comprising:
 a treatment liquid tank that stores treatment liquid therein and is capable of being closed in an air-tight condition; 
 a nozzle connected to the treatment liquid tank through a treatment liquid supply pipe, the nozzle being configured to vacuum-draw the treatment liquid from the treatment liquid tank and to jet the treatment liquid due to vacuum occurring in the nozzle caused by supplying pressurized air from outside of the nozzle thereto; 
 an air suction device branched in the vicinity of the nozzle from the treatment liquid supply pipe and connected to an upper side of the treatment liquid tanks, the air suction device generating vacuum in the treatment liquid tank by drawing in air within an inner space thereof; 
 a positive pressure supply device that supplies a positive pressure gas at a desired pressure to a vacuum space as formed in the inner space of the treatment liquid tank; and 
 a pressure control device disposed between the positive pressure supply device and the treatment liquid tank to adjust the pressure of the positive pressure gas supplied to the treatment liquid tank by measuring a mass of the flow amount of the positive pressure gas: 
 wherein the treatment liquid supply system further comprises 
 a first opening and closing valve (V 2 ) disposed midway of the treatment liquid supply pipe to open and close a supply passage to the nozzle; 
 a second opening and closing valve (V 3 ) disposed on a portion of the air suction device to open and close a fluid line communicating with the treatment liquid tank; and 
 a third opening and closing valve (V 4 ) disposed on a portion of the positive pressure supply device to open and close a positive pressure supply line connected to the treatment liquid tank; 
 wherein the first and third opening and closing valves (V 2  and V 4 ) are initially closed to provide an air-tight condition within the treatment liquid tank while opening the second opening and closing valve (V 3 ) during supply of pressurized air to the nozzle to generate a vacuum within the nozzle, thereby permitting the vacuum to prevail in the inner space of the treatment liquid tank; 
 wherein the second opening and closing valve (V 3 ) is subsequently closed while simultaneously opening the first opening and closing valve (V 2 ) during supply of the pressurized air to the nozzle for permitting a vacuum to be generated in the nozzle which is equal to the vacuum in the inner space of the treatment liquid tank; and 
 wherein the third opening and closing valve (V 4 ) is thereafter opened to regulate the flow amount of the positive pressure gas supplied to the treatment liquid tank in proportion to the mass of the flow amount thereof, so that supply of the treatment liquid from the treatment liquid tank to the nozzle is adjustably minutely controlled based on a difference between the vacuum prevailing within the inner space of the treatment liquid tank and that prevailing in the nozzle. 
 
   
   
     2. A treatment liquid supply system according to  claim 1 , wherein the pressure control device comprises: a mass flow controller. 
   
   
     3. A treatment liquid supply system according to  claim 1 , further comprising:
 a wash liquid tank for storing a wash liquid for washing the treatment liquid tank and the nozzle and capable of being closed in an air-tight condition and connected to an upper surface of the treatment liquid tank, wherein the wash liquid is drawn from the wash liquid tank due to the vacuum occurring in the inner space of the treatment liquid tank and supplied to the inside of the treatment liquid tank. 
 
   
   
     4. A treatment liquid supply system according to  claim 1 , further comprising:
 a wash liquid tank connected to the nozzle, said wash liquid tank storing a wash liquid for washing only the nozzle and capable of being closed in an air-tight condition wherein the wash liquid is drawn from the wash liquid tank due to the vacuum occurring in the nozzle and supplied to the nozzle to wash only the nozzle. 
 
   
   
     5. A treatment liquid supply system according to  claim 1 , wherein the treatment liquid tank, the nozzle, the supply pipes and the opening and closing valves are integrally formed as a single member.